Covering theorems of simplexes and systems of linear inequalities

A selection lemma for Ky Fan's coverings is first proved, and then applied together with Ky Fan's generalization of the classical Knaster-Kuratowski Mazurkiewicz theorem to obtain a new covering theorem of simplexes. As applications, results on the consistency for certain systems of linear inequalities are obtained.     

Generalized quasi-variational inequalities in locally convex topological vector spaces

Let E be a Hausdorff topological vector space and X ? E an arbitrary nonempty set. Denote by E′ the dual space of E and the pairing between E′ and E by 〈w, x〉 for w?E′ and x?E. Given a point-to-set map S: X → 2^X and a point-to-set map T: X → 2^E′, the generalized quasi-variational inequality problem (GQVI) is to find a point $\text{y}\text{?}\text{? S(}\text{y}\text{?}\text{)}$ and a point $\text{u}\text{?}\text{? T(}\text{y}\text{?}\text{)}$ such that $\text{Re}\text{〈}\text{u}\text{?}\text{,}\text{y}\text{?}\text{? x〉 ? 0}$ for all $\text{x ? S(}\text{y}\text{?}\text{)}$. By using the Ky Fan minimax principle or its generalized version as a tool, some general theorems on solutions of the GQVI in locally convex Hausdorff topological vector spaces are obtained which include a fixed point theorem due to Ky Fan and I. L. Glicksberg, and two different multivalued versions of the Hartman-Stampacchia variational inequality.     

König chain for compact matrix sets

A topological proof (via the generalized Gelfand spectral radius formula) is given of the fact that every compact set of complex n×n matrices admits a König chain.     

On certain Matching Properties of Convex Sets

In this paper we use a fixed-point theorem of the Ky Fan typewhich is proved by J.-P. Aubin to give a common generalizationof two matching theorems of Ky Fan concerning closed coveringsof convex sets in topological vector spaces.     

Author index for volume 81

Certain types of integral inequalities which were established by LaSalle, Gollwitzer, Langenhop, Bondge, and Pachpatte are reviewed and unified. The bounds provided by these inequalities can be used in the study of the theory of partial differential and integral equations.